Search PubMed⌕ Search

Biomedical subjects

C F Chen

Publications and source records attributed to C F Chen.

At least 307 records · Page 17Linked to original sources
PubMed1988

Ultrasonic characterization of splenic tissue in myelofibrosis: further evidence for reversal of fibrosis with chemotherapy.

Fibrosis in patients with myelofibrosis (MF) is seen not only in the bone marrow but also around the metaplastic foci in the spleen and liver. Following our observation of reversal of bone marrow fibrosis in MF patients treated with chemotherapy, we undertook ultrasonic splenic tissue characterization studies using sound speed measurements to assess the effect of such therapy on the splenic fibrosis. Single studies in 19 patients showed overlapping ranges among the three sub-groups classified according to the grade of bone marrow fibrosis, but the mean values in these sub-groups showed a trend towards decreasing sound speed with increasing marrow fibrosis. Sequential studies in 9 of these patients showed increased splenic sound speed with decreasing marrow fibrosis in 8 patients following treatment, with a reversal of this pattern seen in 1 patient 1-2 years post-treatment. These results suggest simultaneous reversal of fibrosis in the bone marrow and the spleen in MF patients receiving effective chemotherapy.

Bone Marrow↗
PubMed1988

Changes in epidermal growth factor receptor and its messenger ribonucleic acid levels in human placenta and isolated trophoblast cells during pregnancy.

We measured the amounts of epidermal growth factor receptor (EGFR) in plasma membrane fractions purified from early, middle, and term placentas and from isolated trophoblast cells, and the amounts of EGFR mRNA were measured in whole placentas. Binding studies were performed using [125I] human EGF as ligand; two classes (high and low) of binding sites were found in placental and trophoblast cell plasma membranes. Although dissociation constants (Kd) were not significantly different in placental plasma membranes from the three stages of pregnancy, the number of binding sites increased significantly during pregnancy. The mean numbers of binding sites were 0.72 +/- 0.18 (+/- SE), 1.02 +/- 0.10, and 1.89 +/- 0.21 pmol/mg protein (high affinity sites) in plasma membrane fractions from early, middle, and term whole placentas, respectively. A similar significant increase was found when the membranes were prepared from isolated trophoblast cells. At the same time, total cellular RNA was isolated, denatured, and blotted onto nitrocellulose membranes. Then, hybridization with 32P-labeled pE 7, a cDNA of EGFR, or 32P-labeled v-erb-B oncogene, autoradiography, and densitometry were performed. The EGFR mRNA increased proportionally to the changes in EGFR during pregnancy. These results indicate that EGF-binding sites and EGFR production increase in human placentas throughout the gestational period.

Blotting, Northern↗
PubMed1988

Effects of paweiwan on streptozotocin-induced hyperglycemia in rats.

The ancient Chinese remedy of Paweiwan was used by patients with polyuria, polydipsia, and polyphagia. The present study investigated the hypoglycemic effects of Paweiwan using streptozotocin-induced hyperglycemic rats. The effects on serum glucose in a 4-day course, in a 7-week course, on the standard oral glucose tolerance test, and on the liver glycogen content were studied. In the glucose tolerance test, chlorpropamide and insulin were used as the positive controls and 0.5% CMC (Carboxymethylcellulose) was used as the negative control. We found that Paweiwan decreased the baseline glucose concentration, ameliorated the blood glucose elevation after glucose challenge, and increased liver glycogen content. The results may imply that Paweiwan increases glucose entrance into cells.

Animals↗
PubMed1988

Microencapsulation [corrected] of tumor cells and assay for selecting anticancer drugs.

A microencapsulation of living tumor cells by an improved membrane and droplet forming technique was established in our laboratory. This semipermeable microencapsulating membrane was impermeable to serum albumins (M.W. 66,000 or 45,000) and human hemoglobin (M.W. 64,000), but permitted passage of low molecular weight substances (alpha-Lactalbumin, or Trypsinogen; M.W. 14,200 or 24,000). The in vivo results showed that microencapsulated tumor cell lines (KB, human oral epidermoid cell; P-388 lymphocytic leukemia; GBM 8401/TSGH, glioma) and human colorectal carcinoma cells grew and proliferated exponentially within twenty days. The in vivo growth exhibited better than that in vitro. Histological and morphological findings of these four different kinds of tumor cells are similar to those of original tumor cells. Treatment of the microencapsulated tumor cells (MTC) with cytotoxic drugs (adriamycin, 5-fluorouracil and cyclophosphamide) in vitro showed no significant difference in percent inhibition (p greater than 0.05) between the encapsulated and non-encapsulated cells. The in vivo data indicated that different anti-cancer drugs had different inhibition effects. The results showed that the MTC model was useful for screening an appropriate cytotoxic drug and could be applied to clinical medicine in the near future.

Animals↗
PubMed1987

Neurotensin-like immunoreactivity generated by pepsin from human plasma and gastric tissue.

The present study demonstrates precursors of neurotensin-like immunoreactivity (NTLI) endogenous to human gastric tissue and plasma, and the existence of a gastric NTLI-generating enzyme system. The molecular size of the NTLI-precursors in plasma and gastric tissue were estimated by gel permeation chromatography to be ca 50,000-60,000 and 60,000-70,000 Da, respectively. The neurotensin-like peptide generated from the precursor was detected with a carboxyl-terminally directed antiserum but did not cross-react with an amino-terminally directed antiserum. A neurotensin-like peptide isolated from pepsin-treated human plasma was characterized by mass spectrometry and its amino acid sequence determined. This novel nonapeptide, referred to as kinetensin, failed to affect pentagastrin-stimulated acid secretion or blood pressure in the rat. Sequence homologies between neurotensin, kinetensin and proteins of the serum albumin family suggest a common evolutionary origin and raise questions regarding albumin-like proteins as precursors of regulatory peptides.

Amino Acid Sequence↗
PubMed1987

Effects of bestatin on the central cardiovascular regulatory mechanisms in the rat.

We evaluated the effects of bestatin, the specific aminopeptidase-B and leucine aminopeptidase inhibitor, on the central cardiovascular regulatory mechanisms in Sprague-Dawley rats anesthetized with pentobarbital sodium (40 mg/kg, i.p.). Intracerebroventricular injection of bestatin (100 or 200 nmol/5 microliters) consistently elevated the basal systemic arterial pressure and heart rate. At the same time, this degradative enzyme blocker increased the sensitivity of the baroreceptor reflex responses as well as the efficacy of the modulatory actions of the medullary nucleus reticularis gigantocellularis on these reflexes. We speculate that enhancing the tonic activities of the endogenous neuropeptides in the brain by protecting them from their catabolic enzymes may affect the central cardiovascular regulatory machinery by modifying the operations of the baroreceptor feedback controls and their modulatory mechanisms.

Animals↗
PubMed1987

Turnover of central biogenic amines in one-kidney, one-clip renal hypertensive rats.

Turnover rates, as estimated from the accumulation of the intermediates, 3,4-dihydroxyphenylalanine (DOPA) and 5-hydroxytryptophan (5-HTP) following decarboxylase inhibition, were used to investigate the relationship between central catecholaminergic and serotonergic neurons and the development of hypertension in the one-kidney, one-clip renal hypertensive rats. Results indicated that at one week following clipping, 5-HTP accumulation was decreased in the posterior hypothalamus. At 5 weeks no changes were observed. At 20 weeks higher accumulations of both DOPA and 5-HTP were observed in the medulla oblongata while in the anterior hypothalamus DOPA accumulation was increased.

5-Hydroxytryptophan↗
PubMed1987

The renal functions following a severe hypoxia in conscious rats.

The aftereffects of renal function were studied in rats exposed to hypoxia at 35,000 ft simulated altitude for 60 min. It was observed that the renal handling of a large volume of infused saline was retarded 4 hr after hypoxia, but it was nearly recovered by the end of 24 hr after exposure to severe hypoxia. However, the urine output, plasma and urine electrolytes, and renal hemodynamics were not significantly altered in hypoxic rats. A high mortality of rats exposed to such a low oxygen tension is also reported.

Altitude↗
PubMed1987

Cosmic-ray ionization in the lower atmosphere.

A high-pressure ion chamber filled with 2.5825 X 10(5) kg m-2 argon as used to measure the dose rates of several sites of interest in an attempt to evaluate the dose rates contributed by cosmic rays. Observation sites included two water reservoirs deeper than 110 m, Mount Ali which is higher than 2500 m, airliners flying at altitudes higher than 6700 m, and some sites at sea level. The results of this investigation were compared with those reported by the United Nations Scientific Committee on the Effects of Atomic Radiation and used for the determination of background radiation monitored with thermoluminescent dosimeters and sodium iodide detectors.

Calibration↗
PubMed1987

Clinical sound speed measurement in liver and spleen in vivo.

The paper describes an implementation of clinical sound speed measurement using either a commercial water path scanner or a specially developed dual transducer real time scanner, each interfaced to a general purpose minicomputer for off-line analysis. It describes the examination technique to obtain suitable in vivo clinical data from the liver and the spleen. It develops signal processing methods to achieve clinical confidence in individual measurements. Forty-five liver patients and 46 spleen patients were examined. Sound speed was found to correlate closely with fibrosis content in both the liver and the spleen with an increase in fibrosis resulting in a decrease in sound speed. Sound speed in various pathological conditions are discussed. Clinical results of sequential examinations on patients under treatment are presented and successful monitoring of the disease status is demonstrated. The potential clinical role of sound speed measurement is suggested.

Acoustics↗